How to arrange objects in outward facing circle?
You can model this shape quite easily with just two modifiers.

First add a Cone, set the Vertices to 4 so that it is a pyramid, and lower the Depth to 1.


Set the origin at the bottom of the pyramid. Now Rotate the pyramid so that it is pointing towards the negative Y axis.



Add an Array Modifier, and a Simple Deform Modifier. For the simple deform modifier set the Type to Bend, the Angle to 360, and the Axis to Z.



Use the Count in the Array modifier to change the diameter of the cylinder.


Last add another array modifier to the ring of pyramids, to get more then one row.